This invention relates to fitments for injection devices of the kind in which injection liquid is delivered through a hollow needle. Such devices are used for injecting humans, animals, trees, fruit or vegetables, for example.
Farmers have for many years given routine oral drenches of anthelminthics to suppress the effects of intestinal and other parasitic worms in cattle, sheep and pigs. However, these drenches only become effective after a relatively long period. Although it has recently become possible to achieve the same effect in a much shorter space of time by injecting the animal, there has been a reluctance by farmers to use the new method. This is because it is not usual to sterilise the site of injection either before or after injection. Moreover the same needle is often used for injecting a large number of animals without sterilising the needle between each injection, in view of the large number of animals which have to be injected at one time, so that the site of injection often becomes infected leading to an abscess. Also, especially with sheep, there are several routine injections given to stop various clostridial complications, and each time the animal is injected it increases the risk of rejection of the carcass for human consumption due to abscesses.
Specification U.S. Pat. No. 2,080,688 discloses a fitment for injection devices of the kind referred to in which a sterilising substance is disposed in an enclosure at one end of the fitment for sterilising the point of the needle as it moves through the sterilising substance into the site of injection. However an aperture is provided in an end wall of the enclosure for the passage of the needle into the injection site, and the sterilising substance may become contaminated by way of this aperture prior to an injection being effected. It is an object of the invention to provide such an injection device with increased resistance to contamination of the sterilising substance.